If we go by the weight proportion in the human body, hydrogen is the third heaviest element (10%) after oxygen (65%) and carbon (18%) despite being the smallest and lightest of all elements.

The various compounds that make up the human body all contain hydrogen

Hydrogen is the Most Abundant Element in the Universe – present in just about 90% of the known universe

Hydrogen is the smallest element (one electron and one proton) amongst all the elements in the universe and capable of permeating through almost anything.

Hydrogen plays an important role when Carbohydrates (glucocorticoid) and fats are transformed into energy. The double helix structure of DNA is a result of hydrogen playing the role of bonding the four nucleic acids that make up DNA.